Intermittent headlight issue

[SG1022]

When I am driving, my headlights will start flickering. They do not shut off, they just constantly flicker. They do not always do it, only on some nights. The last time it happened I stopped the car, shut it off, and looked under the hood. I found nothing, but when I started it back up, I did not have the issue again.



Some info on my build:

-74 Charger
-Lights swapped to a 4 high/low 9006 series light set up. So I have four lows, and four highs, and modern lights. All of the wiring is soldered, and wrapped, and done well(might I add).
-New 70 amp or so alternator
-New high/low floor switch(I had to replace this to get it working

I have solid grounds in my engine bay, and my in dash volt meter does not drop when the lights flicker. My dash lights, turn signals, and all other lights do not flicker, and still function properly.

As a side question; are reverse lights only supposed to be on while you are in reverse, but also only when your headlights are on?

[b5blue]

2nd gen Chargers have overload protection inside the H/L switch, 3rd gen's may also, check your FSM. 

[Cooter]

You can't just swap in FOUR high beam lights into an older car and expect the headlight switch to carry that kind of load. Was NEVER designed to do so. You need to put those high intensity lights on relays before you set that thing on fire.

[68neverlate]

Yup, sure sounds like the headlight switch overload protection kicking in.  So, the bad news is, you have and overload in your headlight circuit.  The good news is, your headlight switch overload protection is working and likely prevented your car from being burnt to the ground!   

Relays and headlight circuit wiring upgrades are a must if you're running higher than stock wattage headlights...       

[twodko]

X2. The backup lights only come on when the trans is shifted into reverse. They shouldn't be on at any other time.......at least that's the case with my 69. 

[69_XS29L]

I agree with the overload idea. I have had however a similar problem with two different vehicles, my '72 4x4 and my '69 Charger. The lights would flicker and sometimes go out. Once in my Charger on a Montana two lane back road at about 80 with no moon, voila.... darkness. Once in my truck passing through Idaho at night, I hit the dimmer as I approached a parked Idaho State Trooper, and once again.... night time. He pulled me over thinking l was up to something or hammered. So it was the truck that lead me to the solution to both problems, worn out floor mounted dimmer. I pulled the dimmer from the floor on the side of the road, and built a jumper wire, no problems. This eliminated other possibilities with switches, wires, relays etc.
As far as the backup lights, no way, in reverse only. Bad grounds at the back of the car, old wiring connectors, corroded light sockets, etc. can cause some strange lighting problems as current backfeeds through another ground. I don't have a wiring diagram for your year of Charger, but my '69 manual seems to rule out backfeed. Some other possibilities, some character hacked the tail end wiring for a trailer harness, bungled repair, or behind the dash butchery in search of power for accessory lights. Good luck, cool car by the way.

[Chryco Psycho]

I recommend using relays , simple to install more power to the lights & no load through headlight switch , all modern cars use relays for the headlights & you can use higher output lightswith the relays as well .